Parasitoid avoidance behavior is not triggered by airborne cues in a semi-aquatic bug
Until recently, studies on host-parasitoid interactions have rarely reported the detection and resistance of parasitoids by hosts prior to experiencing a direct attack. Several recent studies have indicated that some hosts have an ability to detect parasitoids without being attacked directly. However, the particular cues used for parasitoid detection have received little attention. We investigate the use of airborne cues (such as volatile chemicals or sound) by the water strider Aquarius paludum insularis (Heteroptera: Gerridae) for detecting its egg parasitoid wasp. Since A. paludum females with previous exposure to the parasitoids oviposit at deeper positions relative to unexposed females, we were able to infer whether A. paludum had detected the parasitoid from oviposition depth. We allowed A. paludum to oviposit after one of the three treatments: exposure to the parasitoid directly, airborne cues (the parasitoid was enclosed in the tube of which ends were sealed by mesh), or wasp absent. The oviposition depth was shallower in A. paludum with exposure to airborne cues than in A. paludum with exposure to the parasitoids directly. The depth did not differ between airborne cues and wasp absent treatments. These results indicate that A. paludum were not able to detect the parasitoid from airborne cues alone.
KeywordsEgg parasitism Parasitoid avoidance Submerged oviposition Detection cue Risk recognition Anti-parasitoid behavior
We wish to express our gratitude to all our colleagues at the Laboratory of Ecological Science, Kyushu University, for their help and encouragement. Particularly, we would like to express our gratitude to Maasa Nobayashi for her invaluable contribution. We also thank Chris Wood for editing the manuscript. This work was supported in part by JSPS KAKENHI Grant numbers 22370010 and 25650149, and by the Environment Research and Technology Development Fund (S9) of the Ministry of the Environment, Japan.
- Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Harley Books, Essex.Google Scholar
- Ferrari, M. C. O., B. D. Wisenden & D. P. Chivers, 2010. Chemical ecology of predator-prey interactions in aquatic ecosystems: a review and prospectus the present review is one in the special series of reviews on animal-plant interactions. Canadian Journal of Zoology 88(7): 698–724.CrossRefGoogle Scholar
- Godfray, H. & J. Charles, 1994. Parasitoids: behavioral and evolutionary ecology. Princeton University Press, Princeton.Google Scholar
- Hirayama, H., & E. Kasuya, 2014. Potential costs of selecting good sites for offspring: increased risk of drowning and negative effects on egg production. Ethology 120(12): 1228–1236. doi: 10.1111/eth.12296.
- Holm, S., 1979. A simple sequentially rejective multiple test procedure. Scandinavian Journal of Statistics 6: 65–70.Google Scholar
- Kats, L. B. & L. M. Dill, 1998. The scent of death: chemosensory assessment of predation risk by prey animals. Ecoscience 5(3): 361–394.Google Scholar
- Kohmura, H. & H. Hirayama & U. Takatoshi, in press. Diving into the water: cues related to the decision-making by an egg parasitoid attacking underwater hosts. Ethology. doi: 10.1111/eth.12326.
- R Core Team (2013). R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria [available on internet at http://www.R-project.org/].